The widely spreading use of maintenance hemodialysis and the prolongation of life of uremic patients has been accompanied by an increase in incidence of renal osteodystrophy. Recently attention has been focused on the attending dental problems in these patients. Radiographic evidence of alveolar bone demineralization and loss of lamina dura associated with increase in tooth mobility has been reported. This study is designed to investigate the effects of experimenttally induced renal insufficiency on the alveolar bone of adult male dog. Bone changes will be determined by a quantitative histological technique on thin non-decalcified sections. Time spaced tetracycline labeling will be used for the study of the kinetics of bone turn over. A comparison will be made between the alveolar bone changes and those occurring in the rib of the same animal. The efficacy of Vitamin D as a therapetuc agent will be investigated.